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RINEX File Processing

RINEX (Receiver Independent Exchange Format) files contain raw GNSS observation data that can be post-processed to determine highly accurate coordinates. This guide covers RINEX file naming conventions and recommended processing services.

RINEX File Naming

Standard Naming Convention

RINEX files follow a standardized naming format that encodes important metadata:

SSSSDDDF.YYT
Component Description Example
SSSS Station identifier (4 characters) BASE
DDD Day of year (001-366) 045
F File sequence number (0-9, A-Z) 0
YY Two-digit year 24
T File type o = observation, n = navigation

Example: BASE0450.24o = Observation file from station "BASE" on day 45 of 2024

Resources

Resource Description
RINEX Version 2.11 Specification Official format documentation including standard file naming
NOAA Day of Year Calendar Convert calendar dates to day-of-year

RINEX Processing Services

After collecting RINEX data from your FastRTK base station, submit it to one of these free online processing services to obtain precise coordinates.

OPUS (Recommended for USA)

NGS OPUS: Online Positioning User Service

OPUS is the recommended service for users in the United States.

Feature Details
Provider NOAA National Geodetic Survey
Coverage United States and territories
Coordinate Output NAD83 (2011) epoch 2010.0, ITRF14 epoch of data collection
Height Output Both ellipsoid and orthometric heights (NAVD88 in US)
Accuracy Metrics Peak-to-peak errors for each coordinate component
State Plane Outputs state plane coordinates when applicable

OPUS Requirements

Requirement Minimum
Observation Duration 2 hours (Static), 15 minutes (Rapid-Static)
Data Rate 30 seconds or less
Antenna Type Must select correct antenna model

[OPUS Tips]

  • Use OPUS-Static for observation sessions of 2+ hours
  • Use OPUS-RS (Rapid Static) for sessions of 15 minutes to 2 hours
  • Longer observation times yield better accuracy
  • Submit during off-peak hours for faster processing

AUSPOS

Geoscience Australia Online GPS Processing Service: AUSPOS

AUSPOS is an alternative service with global coverage.

Feature Details
Provider Geoscience Australia
Coverage Global
Coordinate Output ITRF14 epoch of data collection
Accuracy Metrics 95% uncertainty values for each coordinate direction
Processing Engine Bernese GNSS Software
Network Solutions Submit multiple concurrent observations for networked processing

AUSPOS Considerations

[Coordinate Conversion Required]

AUSPOS outputs coordinates in ITRF14. For use in the United States, you must manually convert to NAD83 (2011) epoch 2010.0 using the NGS HTDP Tool.

Feature OPUS AUSPOS
Best For United States Global / Australia
Native Datum NAD83 (2011) ITRF14
Orthometric Heights Yes (US) No
Network Solutions No Yes

Processing Workflow

Step 1: Download RINEX from FastRTK

  1. Log into your FastRTK dashboard
  2. Navigate to RINEX section
  3. Select the date range for your observation
  4. Download the observation file (.obs or .rnx)

Step 2: Submit to Processing Service

For OPUS:

  1. Go to OPUS
  2. Upload your RINEX observation file
  3. Enter your email address
  4. Select your antenna type from the dropdown
  5. Enter the antenna height (if different from default)
  6. Click Upload to Static or Upload to Rapid-Static

For AUSPOS:

  1. Go to AUSPOS
  2. Upload your RINEX observation file(s)
  3. Enter your email address
  4. Select antenna type and enter height
  5. Submit for processing

Step 3: Review Results

Processing typically takes 5-15 minutes. You'll receive an email with:

  • Processed coordinates in multiple reference frames
  • Accuracy estimates / uncertainties
  • Processing quality indicators
  • Recommended coordinates for your base station

Best Practices

Observation Duration

Duration Expected Horizontal Accuracy
15 minutes 2-5 cm
1 hour 1-2 cm
2 hours < 1 cm
4+ hours Sub-centimeter

Data Quality Tips

  1. Minimize obstructions - Ensure clear sky view during observation
  2. Stable antenna mount - Prevent any movement during collection
  3. Avoid multipath - Keep antenna away from reflective surfaces
  4. Note antenna height - Measure accurately to antenna reference point
  5. Check satellite count - Aim for 8+ satellites throughout observation

Related Documentation